Wireless telegraphy.



R. C. GALLETT I.

WIRELESS TELEGRAPHY,

APPLIUATION FILED DEC. 20, 1907.

Patented June 7, 1910.

3 BHEBTSSEEBT 1.

R. G. GALLBTTI. WIRELESS TBLEGRAPHY. APPLICATION FILED 1:30.20, 1907.

Patented June 7, 1910.

a sums-sum 2.

- R. 0. GALLETTI. WIRELESS TBLEGRAPHY. AiPLIOAIION FILED DBO. 20, 1907. I 960,304, r Patented June '7, 1910.

3 SHEETSSHBET 3.

ROBERTO c- GALLET'III, or ROME, ITALY WIRELESS. TELEGRAPHY.

To all whom it may concern:

Be it known that I, ROBERTO C. GALLETTI, a subject of the King of Italy, residing at Rome, in Italy, have inventedcertain new and useful Improvements in Wireless Telegraphy, of which the following is a specification. 1

This invention relates to wireless telegraphy and has for its object to provide a novel arrangement 'ofapparatus whereby the energy transmitted is more effectively utilized. W

A feature of the invention is that a source ofcontinuous oscillations is employed, produced for example by Poulsens method, but the oscillations are only'transmitted in periodic groups each containing only that number of oscillations which is necessary to attain the steady 'state for the particular transmitting aerial, and its corresponding receiving aerial, so as to obtain the maxi ectin the a receiving This result is obtained according to t e present invention by employing a circuit for accumulating oscillations in between the source ofcontinuous oscillations and'the' "aerial, a contact device or commutator making -periodic connection to the aerial. In-

telegraphy by Morse signs, about 20 groups of oscillations per second are suflicie'nt. -If a given wireless telegraph system comprising transmitting and receivlng aerials need the fraction of a second if to reach the steady state, then the circuit accumulating the oscillations may furnish to the aerial in each second 20 groups of oscillations of the total duration 20 t, while it absorbs energy from the source of continuous oscillation uninterruptedly during the whole second. The

power of transmission is increased in the ratio e er-iodical emission of electr1c oscillatlons mm the transmitting station for each group of duration t with intervals or lapses-of t, it is evident that'the connection between the receiving aerial and the system 'of receiving circuits is onlyof advantage during the time t in which the] f oscillations arrive, while during the intervals .23 the connection to. the aerialea disadvan tage-finjhat the aerial during-this time rapapparatus.

t and the maximum syntonic effects inherent with the steady state, 2'; e., the

maximum value, are at-' Specification of Letters Patent. Application filed December 20, 1907. Serial No. 407,298.

' eral ly in Patented June 7, 1910.

idly dissipates the energy already connnunicated by 1t .to the other circuits which genpractice have a small damping coefficient.

A further feature of the invention is that a commutator or contact-making device is therefore employed. in connection with the receiving aerial as well as with the transmitting aerial, the receiving'contact device operating synchronously with the periodical transmission so avoiding the disadvantages of having the receiving aerial in permanent connection with the receiving circuits as justexplained.

Another feature of this invention is an arrangement of contacts in a'commutator of the type just referred to so that one aerial may act as transmittin .and receiving station at the same time, th ereby providing for a duplex system of telegraphy.

Other features of this invention will be evident from the following description taken in connection with the accompanying drawings, in which- Figure 1 is a diagram of the circuits em ployed; Fig. 2 is an elevation of the contact-- making device; Fig. 3 is a plan of the same; Fig. 4 shows diagrammatically thecircuits employed at the transmitting and receiving stations; Fig. 5 shows diagrammatically one form of commutator adapted to be used with the arrangement of circuits shown in Fig. 4:; Fig. (5 shows diagrammatically the circuits employed at one station for duplex telegraphy; and Fig. 7 shows diagrammatically one form of commutator device adapted to be employed with the circuits shown in Fig. 6. v

Referrin to Figs. 1, 2 and 3, A represents the aerial, is a circuit for accumulating oscillations, consisting of a condenser of considerable capacity relatively to the wavelength employed and of somuch inductance in the spirals'of thick wire between the terminals of the condenser asfor inductive connection with of the continuous oscillations and with the aerial A; and for obtaining an oscillation of a period identical or in harmonic relation with theperiod of oscillation in A and in C. The circuit B is of very small resistance'a-s it is preferably closed without a spark,-

the source C though a short spark might be employed.

The'circuit B is immersed in insulating oil I is necessary tionwiththe aerial during the instant t deg to avoid losses by brush discharge, etc.,

caused by the high potential employed. The

circuit B cannot emit oscillations except by means of the aerial because no straight wires are employed-in its formation and said circuit is not a 'good' radiator because it .is" 7 closed and becausethe persistence .of the same is hi h. Thewire which leads from the aerial to the earthT has a'loose ductive coupling with the circuitvB; .Flhe contact-making device for making connecsired with intervals of may be a disk of insulating material D, Figs.

2 and 3, provided with a segment of-platiwhich might be transported on to,th e insi ilatinf portion D or float in the air. avoi t e long spark which otherwise would take place on breaking the connection with the aerial, and also to avoid the energy ac-- cumulating in the aerial. from being lost in waves of various len hs, a secondcontact it is provided which eads to the earth T through a wire which forms with the aerial I .an oscillating system of the-same period as "'AhT when the disk in its rotation joins 7o 40 1 hereinbefore stated that the length of time .to' a before disconnectin a from h. k may be kept constantly joine to a.' 'It has been t of each group of oscillations is preferably I 7 so established, that durin thetime t-i-t the 1; accumulating circuit .0 thetransmitting cuit B of'the receiving station may the circuits joinedto them, nee

' made'equal to that time which the transmitting and receivin aerials, or more precisely. the systemof t e aerials to ether with to obtain the steady state. If the time interval '25 be stationmay not have attained its own steady state without the aerial and may have usefully accumulated energy and that the cirhave usefully stored part of the energy glven to it by its aerial, then it is evident that the maximum efiiciency both of transmission and of reception is really to be obtained by using commutating or contact-making devices making periodical connection tothe aerials in such fashion that these enter into action for a certain time not greater than t and are detached for a certain interval not greater than t. When continuous oscilla-- tions are employed, the power of transmission is increased more or atelyto-the ratio I If! and t bedetermined experimentally proportionstrength ;of signals then. f the most useful .frequency of commutation ismalso' determined being given by the formula I n'telegraphy by Morse it 'is -'sufli-' cient if the'number fbe greater than 20'; l

In Fig.4 A is the transmitting aerial; C is the source of continuous'oscillations and B the circuit for accumulating the oscillations, a contact-making device being employed to join a toh and 0, to I: as hereinbe or'e fully explained. At the-receiving station A is the aerial, B the receiving resonant'circuihhl for two stations so 'as' to obtain the greatest is'a contact to the receivingwire con'nected i to earth at T a is a contact on'the aerial,

k isa contact to a circuit connected'to' earth at T, forming with the aerial an oscillating system of. the same eriod as A k 1;

ing material which is rotated-at the rate of 7 turns per second. On the disk aref portions of metallic rings a- 7 a Tconnectedfl as pre- The contact-making device or commutator shown in-Fig. 5 consistsof adisk of'insulatviously mentioned to 'theaeiial A, Brushes bear on these ringsa}. 0}. these brushes forming the contacts h 70 Ihe an to 2 1r ft. It will be evident t erefore 'that the aerial is connected to thecontact h i during an interval t as required-and during an.

interval t with the contact 70 The-wirebe tween 70 and T forms withv the-aerial a.

resonant system of the same length of wave adopted for use between the two stations and prevents the aerial on making and breaking connection with h from developing sparks as would happen in certain electric condi-- tions of the atmos here.

Referring to Figs. 6 and 7, for duplex circuits are connected to a single commutator (Fi 7), in such a manner that at every turn of t e commutator or contact-making device the aerial is successively in contact with k for the time t, with k, for the time and with k for the time t, with k for the time 5 I v The synchronous commutator. in the correspondin station precedes or is retarded by an ang e 1r. When for particular reasons telegraphy the transmission and'receiving it is impossible to so arrange matters that the initial period of oscillation of the circuit E the aerial being removed, be equal to or in harmonic relation with the period of the oscillations which are developed when the aerial enters into action, one must employ additional circuits connected to d (Z .as shown in Fig. '6. The circuits connected to (Z and d which areshown in Fig. 6 already referred to may consist of wire Wound in spirals joined to earth through a condenser. They have the same time-constant of oscillation as the aerial but have a minimum dam ing coefiicient. rings (1 and d on the connnutatorshown in Fig. 7 are for the connections to d and d shown in Fig. 6. While a is in connection with h, d is in connection with k and vice versa, and while a is in connection with 70 al is in connection with-k and vice versa.

tion.

The portions of' metallic When a is in contact with h, d continues in contact with h, and when a is in contact with h, d continues with h.

What I claim as my invention and desire to secure by Letters Patent is-' A system of Wireless telegraphy in which a closed oscillating circuit is used to accumulate energy which is emitted periodically by an antenna, the duration of the emission of the energy by the antenna being continued until the emission reaches the steady condi- In testimony whereof I have signed my name to this specification in the presence" of two subscribing witnesses.

R. C. GALLETTI.

Witnesses:

GHERRA CARTANN, Y H. D. JAMESON. 

